# decodeEnvelope

> **decodeEnvelope**(`data`): [`DecodedEnvelope`](/reference/filoz/filecoin-encryption-envelope/namespaces/cose/interfaces/decodedenvelope/)

Defined in: [packages/filecoin-encryption-envelope/src/cose/decode.ts:109](https://github.com/FilOzone/synapse-sdk/blob/5e9df029417d95928e523b01a29bf523e42db418/packages/filecoin-encryption-envelope/src/cose/decode.ts#L109)

Decode the envelope at the start of `data`.
Bytes after `envelopeLength` are untouched detached ciphertext.

## Parameters

| Parameter | Type |
| ------ | ------ |
| `data` | [`Uint8Array`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array) |

## Returns

[`DecodedEnvelope`](/reference/filoz/filecoin-encryption-envelope/namespaces/cose/interfaces/decodedenvelope/)